The Effect of Combined Processing on Residual Stresses in the Surface Layer of Power Plant Parts

The purpose of this research was to analyze the change in residual stresses in the surface layer of steel samples taking into account the technological heredity effect on the value and sign of residual stresses. An installation of combined processing was developed. Combined processing consists of sequentially performing electromechanical processing and diamond smoothing. All areas of the samples were studied—after machining (i.e., in the initial state), after electromechanical processing, and after diamond smoothing. The research shows that the sign and value of residual stresses are significantly affected by the combined processing modes. The main parameters of the surface layer are formed at the final stage of the combined processing–diamond smoothing. This paper gives recommendations on the use of combined processing for power plant parts.

ASSESSMENT OF THE IMPACT OF TECHNOLOGICAL HEREDITY ON INDICATORS OF RELIABILITY, DURABILITY AND ENVIRONMENTAL SAFETY OF ELEMENTS OF GAS TRANSMISSION SYSTEMS

Modern gas transmission systems are power facilities based on a main pipeline, which is a continuous pipe, along which devices are placed that provide gas pumping at predetermined parameters. Unlike other linear structures, such as roads, railways, the main pipeline throughout the entire period of operation is in a complex stress state under the influence of the internal pressure of the pumped product and functions as a pressure vessel. The operational reliability, durability and environmental safety of gas transmission systems are ensured by various control devices and pipe fittings. The article discusses issues related to predicting the operation of pipe fittings during the operation of the gas transmission system, while ensuring the required reliability, durability and environmental safety. An analysis of the phenomena of technical heredity is given, with the help of which it is possible to determine the causes of deviations in the output parameters of pipe fittings in the process of their manufacture or repair. It has been proved that the main feature of technological heredity is the transfer of a certain technological property from the previous technological operation to subsequent ones, characterized by the transfer coefficient of technological heredity. An indispensable condition for the monotonicity of changes in the transmission coefficient of technological heredity in order to ensure the required quality of manufacture or repair of pipe fittings is revealed. The economic principle of predicting the quality of manufacturing or repair of products is proposed for use, a relationship is found between the initial and output technological properties of pipe fittings, a route is chosen to achieve the required quality of its manufacture or repair, including procurement and finishing technological operations.

Determination of technological heredity when machining holes in parts of gas turbine engines

Calculation of parameters that determine technological heredity during drilling and the ability to control the process of technological heredity. Keywords: drilling, cutting force, drift, hole axis, depth and degree of hardening, technological heredity. [email protected]

Controlling turning contouring of shaped parts

The machining of contoured shaped surfaces of parts with a circular cross-section is executed on CNC lathes using control programs. All known CAM systems offer canned cycles for such surfaces. In most cases, it is recommended to use G71, G72 and G73 canned cycles for roughing contouring. The aim of the study is to analyze the cutting processes in roughing and finishing and to assess their influence on the surface quality of the part. A modeling technique is proposed, which is based on the use of an original application soft that allows simulating all machining cycles with fixing the results in the form of oscillograms of changes in the depth of cut. Comparative analysis of the results allows you to choose the most acceptable machining cycle for a specific profile of the contour of the part. The developed program also makes it possible to obtain the predicted accuracy of machining along the entire contour, which may arise as a result of technological heredity. In addition, the array of data on cutting depth obtained during the simulation, which is the main disturbance of the process, allows one to design the law of control of the cutting mode, for example, on the feed, which will lead to the stabilization of the cutting process. Анотація. Обробка контурних фасонних поверхонь деталей, що мають круглий поперечний переріз, виконується на токарних верстатах з ЧПУ по керуючим програмами. Всі відомі САМ-системи пропонують стандартні цикли для обробки таких поверхонь. У більшості випадків рекомендується застосовувати стандартні цикли чорнової контурної обробки G71, G72 і G73. Метою дослідження є аналіз процесів різання в чорновий і фінішної обробки і оцінка їх впливу на якість поверхні деталі. Порівняльний аналіз результатів дозволяє вибрати найбільш прийнятний цикл обробки для конкретного профілю контуру деталі. Розроблена програма також дозволяє отримати прогнозовану точність обробки по всьому контуру, яка може виникнути в результаті технологічної спадковості. Крім того, отриманий під час моделювання масив даних по глибині різання, який є головним обуренням процесу, дозволяє спроектувати закон управління режимом, наприклад, з подачі, які призведе до стабілізації процесу різання.

Technological features of anode dissolution in a combined hardening treatment when developing high-speed rotors

Is studied of the features of anodic dissolution in the process of local combined processing of metal removal points with surface defects arising during balancing of high-speed rotors in connection with the softening of working surfaces from unwanted technological heredity. The ways of improving the processes of their technological refinement using local hardening methods are shown, calculation formulas are given technological parameters of the anode process.

Experimental studies of the influence of technological heredity on the damage to wheels of high hardness

The influence of technological heredity on the interaction of the wheel and rail is considered. The state of the surface of the samples for the presence of contactfatigue defects is estimated. A relationship is established between the maximum height of waviness on the surface of the roller and the rate of damage to its surface. The dependence of the number of loading cycles of the rollers on the height of the waviness and the distribution of the run of the wheels of increased hardness between the turnings are constructed, which is consistent with experimental data. Keywords wheel, rails, contact-fatigue processes, technological heredity, wear, fatigue defect, wheel of increased hardness. [email protected]